We would not have such a plane mystery if all international planes implemented the use of an automatic transmitter sending continual (can’t be interrupted) radio burst data transmitting the GPS reading, time, altitude and the plane’s unique identifying number to land-based control centers. This radio information would be handled through satellite. This method would be a much-needed supplement to radar tracking, making it virtually impossible to lose another plane. The signal can be easily encoded for security concerns.
Even more important — assuming the plane was hijacked — if this equipment had been installed in the Malaysian airplane, a hijacker would be unable to hide the plane location by simply turning off the transponder. I wonder if anyone would have attempted to hijack that plane under those circumstances.